An investigation is under way into the mystery death of a former Macclesfield schoolboy who fell ill in police custody after an armed siege.

Armed police swooped on the home of suspect Darren Lyons, 43, after reports of a man making threats to kill, with access to weapons.

Officers were at the address on Beech Drive in Kidsgrove for a three-hour stand-off before arresting Mr Lyons, known as Daz, who was a pupil at Fallibroome Academy.

Mr Lyons, who had barricaded himself in, was taken into custody where he became seriously ill and died three days later in hospital.

The Independent Police Complaints Commission (IPCC) has launched an investigation.

Bernard Hurst, 61, a former assistant principal at Fallibroome, said he clearly remembers Darren, who attended the school from 11 to 16.

Bernard, who retired in 2011 but still helps at the school, said the news about Darren’s death came just as he was creating a ­ page for a new Fallibroome alumni association.

One of the first pictures he uploaded features Mr Lyons on a trip to Koblenz in Germany.

He said: “It was bizarre, I’ve been putting up old pictures and found one of Darren, just before I heard about what happened to him. It’s shocking.

“He was a larger-than-life character and boisterous, but in a nice way, with a good sense of humour.”

Police were called to the house Mr Lyons shared with his elderly grandmother Pauline Cegis, on Beech Drive, Kidsgrove. Police recovered an air rifle and bladed weapons from the address.

Mr Lyons was taken to the North Area Custody Facility in Etruria where he was put in a cell under observation.

At around 11pm officers found his health had deteriorated and he was taken to University Hospital of North Staffordshire, where he died.

James Dipple-Johnstone, IPCC commissioner, said: “We are carrying out an investigation into the arrest and care given to Mr Lyons during the several hours he spent in custody.”

ACC Nick Baker, from Staffordshire Police, said: “Whenever someone sadly dies following contact with the police, it’s absolutely right and proper the circumstances are fully investigated.”

Darren’s mum Diane Lyons, who lives in Congleton, declined to comment.

His dad Tony lives in Stoke-on-Trent. Mr Lyons’ funeral was at St Mary’s Church, Astbury, near Congleton, on Monday.